This invention relates to lifting devices for railway tank cars.
AAR Mechanical Division Circular D. V. 1897 specifies that new cars ordered after July 1, 1978 be provided with connecting lugs or rings four places on the car. The rings or lugs are to be utilized to lift the car when it is essentially upright and is within 15.degree. of the vertical, and each ring or lug should be able to support 40 percent of the gross weight of a loaded car. It has been proposed to increase the angle up to 45.degree. of the vertical. It is contemplated that the rings or lugs will be located at opposite ends of the car below the tank on either side of the body bolster adjacent the side sill.
However, the presence of such rings or lugs presents a serious potential problem for misuse. Wreck clearance crews may improperly rely on lifting lugs to drag or lift overturned cars. Possible consequences of such misuse are damage to the bolster and/or the tank. For example, the lifting force may tear the body bolster from the tank body and/or cause a crack in the tank body which would cause lading to spew out, causing damage to persons or property.
It, therefore, would be desirable to provide a lifting lug assembly or arrangement in which the lifting hook cannot be attached to the ring or opening in a lug unless the direction of lift is within 45.degree. of the vertical axis of the tank.